I don't think anyone is using cloth diapers for frugal reasons, but rather for waste and environmental reasons that disposable diapers create (It takes hundreds of years for each disposable diaper to decompose, and they are made with plastic and carcinogens). I've looked into the topic, and although it might discount the cost of constant purchase of disposables, the high cost of the cloth ones themselves as well as the cost of running the washing loads mean the reason to switch wouldn't be for frugal reasons but to stop the influx of disposable diapers into landfills and comfort of the baby wearing it.